Verification of Time Information transmitted by Time Signals or Time Telegrams

• US 20170280402A1
• Filed: 03/22/2016
• Published: 09/28/2017
• Est. Priority Date: 03/22/2016
• Status: Active Grant

• Current Assignee: Christoph Ruland
• Original Assignee: Prof. Christoph Ruland
• Inventors: Ruland, Christoph, Schneider, Matthias
• Granted Patent: US 10,165,530 B2
• Time in Patent Office: Days
• CPC Class Codes: H04W 12/10 Integrity
• CPC Class Codes: H04W 12/61 Time-dependent
• CPC Class Codes: H04W 12/67 Risk-dependent, e.g. selecting a security level depending on risk profiles
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A method is proposed for verification of time data from a time signal modulated on a continuous carrier signal with steps to receive a first time signal with a first reference time, to receive a second time signal with a second reference time, which follows the first reference time in time, for calculation of the target time interval lying between the reference times from the time data contained in the received time signal, to determine a time interval and determine a reference time interval, using counting of periods of the continuous carrier signal within the time interval, for comparison of the target time interval with the reference time interval and to send an error signal, if the deviation determined by the comparison surpasses a stipulated tolerance value.

Claims

1. A method for verification of time information from time data modulated on one or more continuous carrier signals, comprising:

receiving a first time signal or telegram with a first reference time;

receiving a second time signal or telegram with a second reference time which follows the first reference time in time;

calculating a target time interval between the first time information and the second time information from the time data contained in the received first and second time signal or telegram or from the preceding verified time information and the second time signal or telegram

determining a reference time interval by counting of periods of the received signal within the actual time interval between the first and second reference time

comparing the target time interval with the reference time interval; and

outputting an error signal, if the deviation determined by the comparison surpasses a stipulated tolerance value.

2. The method according to claim 1, wherein, for verification of time information from the first and second time signal transmitted in a fixed time grid and for determination of the reference time interval, the method includes counting periods of the one or more received signals in the actual time interval between the first and second reference times determined by the first and second received time signals.

3. The method according to claim 1, wherein:

the first time information and the second time information are comprised in time telegrams transmitted in packet-oriented mode from a loose time grid; and

for determination of the reference time interval, the method includes counting periods of the one or more received signals in the actual time interval between the first and second reference times determined by the first and second received time telegrams; and

for determination of the reference time interval, the method includes counting periods of the one or more received signals in the time interval between the end time of the first and the start time of the second received time telegram and

the addition of the packet transmission time to the already counted periods.

4. The method according to claim 3, further comprising determining the packet transmission time by counting the periods of the received signal during transmission of the packet, which contains the time telegram.

5. The method according to claim 3, wherein a pre-determined value is added as the packet transmission time.

6. The method according to claim 1, further comprising weighting the counted periods with the period times that vary by frequency modulation during counting the periods of one or more frequency-modulated received signals.

7. The method according to claim 6, further comprising establishing variation of the period time of the frequency-modulated received signal according to data derived from it by demodulation.

8. The method according to claim 1, further comprising establishing counters for counting the periods during the different states of the applied modulation scheme used for modulation of time data on one or more continuous carriers. The counters correspond to the data derived by demodulation of the one or more received signals. For example, if the first bit of a bit run of bits with value 0, counter 1 is started or restarted, at the first bit of a bit run of bits with value 1, counter 2 is started or restarted. When one counter is started, the other counters are stopped. When the counting of periods is finished for determining a reference time interval, the states of the counters are used to calculate the time interval, which passed during counting the periods.

9. A device for providing a remotely synchronized verified time base, the device comprising:

one or Receiver-Frontend for receiving one or more signals with modulated time signals or time telegrams;

one or more Frame-Synchronization Units to extract time signals or time telegrams from the one or more demodulated received signals and to mark a reference time interval;

one or more Decoders to decode the time data from the time signal or time telegram;

one or more Reference-Time-Interval-Measurement Unit to count the periods of the received signal. The counting of periods of the received signal is controlled by the marks of the Frame-Synchronization Unit;

for different states of the modulation scheme different counters are used;

the counted periods are used to calculate the reference time interval;

one or more Target-Time-Interval-Calculation Units to calculate a target time interval lying between time information from time data contained in the received time signals or time telegrams;

one or more Time-Interval-Comparison Units to compare the target time interval with the reference time interval and to send an error signal, if the deviation determined by the comparison exceeds a stipulated tolerance value;

one or more Control Units to forward the trustworthy time information and process the error handling;

one Time-Synchronization Units to process one or more trustworthy time information for evaluation and optimization;

the output is the verified time information delivered to application processes, e.g. actuators.

10. The device according to claim 9, wherein the Receiver-Frontend is designed as tuned radio frequency receiver.

11. The device according to claim 9, wherein the counted periods are periods of a rectified received signal.

12. The device according to claim 9, wherein the device is designed as a billing unit in a charging station, a taximeter, a wind power unit, solar unit or as another unit in which time-dependent actions are conducted and in which correctness of an available time base must be present.

13. The device according to claim 9, wherein the device is designed as a time service calculator, time server, trusted platform module or hardware security module.

14. An electronic control system for synchronizing a time base comprising:

a Receiver-Frontend Unit for receiving a sequence of time signals or time telegrams modulated on a carrier signal, having a first output for outputting a sequence of data, each data sequence containing one of the demodulated time signals or time telegrams and a second output for outputting an output signal allowing to count the periods of the received signal. The second output can be given in an analog or digital representation.

a Frame-Synchronization Unit being coupled to the first output, which extracts the time signal or time telegram from the first output of the Receiver-Frontend Unit and determines the reference time of the time signal or telegram.

a Reference-Time-Interval-Measurement Unit being coupled to the second output of the Receiver-Frontend Unit, wherein the Frame-Synchronization Unit is coupled to a control input of the Reference-Time-Interval-Measurement Unit for applying a start signal upon recognition of a first reference time of a first time signal or telegram in response to which the Reference-Time-Interval Unit starts counting the periods of the received signal and for applying a stop signal upon recognition of a second time reference of the next succeeding valid time signal or telegram in response to which the Reference-Time-Interval-Measurement Unit stops counting the periods of the second output of the Receiver-Frontend Unit, the Reference-Time-Interval-Measurement Unit being configured to calculate the actual reference time interval using the counted periods and a predetermined frequency or frequencies of the carrier or received signal, wherein the Reference-Time-Interval-Measurement Unit has an output for outputting the actual reference time interval signal being representative of the calculated actual reference time interval,

a decoder for decoding the demodulated time signals or time telegrams to extract the time information,

a Target-Time-Interval-Calculation Unit for a calculation of a target time interval between the time information received with the first one of the time signals or telegrams and a second time information received with the second one of the time signals or telegrams and for providing a target time interval signal being representative of the calculated target time interval,

a Time-Interval-Comparison Unit for receiving the reference time interval signal from the Reference-Time-Interval-Measurement Unit and the target time interval signal from the Target-Time-Interval-Calculation Unit, the Time-Interval-Comparison Unit being adapted for calculating a difference between the time reference interval and the target time interval and for comparing the difference to a threshold value, wherein the Time-Interval-Comparison Unit outputs the actual time information and a confidence signal being expressive of the correctness of the actual time provided that the difference is smaller than the threshold, wherein the time base is synchronized using the target-time interval that is output by the target-time calculation unit only if the confidence signal is output by the time interval comparison unit. Optional additional information can be output, e.g. the target time interval.

A Control Unit for processing and forwarding the output of the Time-Interval-Comparison Unit and error handling, whereby errors can be generated from all other units. Control Unit can monitor the sequence of confidence values to detect trials of clock manipulation.

15. The electronic control system of claim 14, wherein the received signal is a modulated signal or a plurality of modulated signals modulated by frequency, amplitude, phase or combination of them, and/or multiplexed by spreading techniques, e.g. Code Division Multiplexing Access (CDMA).

16. The electronic control system of claim 14, wherein the received signal contains a sequence of time signals or time telegrams, e.g. a space-based global positioning signal (GPS), a time signal radio station based signal, a radio ripple control based signal, a wired ripple control based signal or a terrestrially-based enhanced long-range navigation signal.

17. The electronic control system of claim 14, being adapted for parallel processing of a plurality of a sequence of time signals or time telegrams modulated on carrier signals received concurrently to obtain a set of target-time intervals, reference-time intervals and respective trustworthy time information and confidence signals, and further comprising a Time-Synchronization Unit for receiving the set of trustworthy time information and confidence signals for processing in order to generate a resultant verified time information that is used for synchronizing the time base.

18. The electronic control system of claim 17, the Time-Synchronization Unit being configured to calculate a resulting value for the set of trustworthy time information for which a confidence signal is present to provide the verified time information for synchronizing the time base.

19. The electronic control system of claim 14, being coupled to one of a billing unit in a charging station, a taximeter, a wind power unit, a solar unit, an actuator.

20. The electronic control system of claim 14, comprising a hybrid analogue-digital integrated circuit chip implementing the Receiver-Frontend, the Frame-Synchronization Unit, the Reference-Time-Interval-Measurement Unit, the Decoder, the Target-Time-Interval-Calculation Unit the Time-Interval-Comparison Unit and the Control Unit.